The present invention relates to packaging and in particular to an improved method for forming a reclosable package, in situ, on vertical form and fill equipment.
In U.S. Pat. Nos. 3,827,472 and No. Re 28,969 there is disclosed a reclosable package formed from a plastic film material. The film is provided with male and female zipper profiles which form mating closures for the final package. As discussed in U.S. Pat. Re 28,959, in order to insure that the profiles of the final package will properly align with each other, the profiles of the film must be joined together before cross seams are made transverse to the profiles to form the sides of the package.
In vertical form and fill machines a plastic sheet is drawn across a forming collar past and around a filling spout. The film is first seamed longitudinally to form a tube which is then seamed transversely before a product is dropped into the tube from the spout and then seamed again transversely after the product is introduced to thereby form a package about the product. The second transverse seam then serves as the first seam for the next package and the process is repeated.
While it is often desirable to package products normally filled on form fill equipment in reclosable packaging, it has not been possible to do so heretofore with conventional form fill equipment because of the difficulties in handling the profiles. While the profile could be joined before the film is formed into a tube it should be realized that if the profiles are so joined they must somehow be brought over the forming collar in such a manner as to insure that the profiles do not inadvertently open during the package forming process.
In view of the above, it is the principal object of the present invention to provide an improved method of forming reclosable plastic bags, in situ, on vertical form and fill equipment;
A further object is to provide such a method wherein the bags may be formed with a minimum amount of modification of the form filling equipment;
A still further object is to provide a simplified apparatus for effecting the above method.